Hazardous location applications

EX systems refer to work equipment relevant to explosion protection, such as tank farms in the chemical industry, refineries, gas stations and biogas systems.

Explosion protection systems

Under the operational safety regulation BetrSichV, EX systems are the “total of work equipment relevant to explosion protection”. These are subject to special requirements and regular checks due to the risk of explosion that they pose and represent a significant safety risk for the environment. The most important terms associated with EX systems are explained below.

Systems in explosive areas

Explosion protection is a buzzword that almost every company has to deal with at some point. This means that the operator is always obliged to subject his systems and work equipment to a fundamental risk analysis and to ensure compliance with the applicable standards. If it is determined that there is an increased risk of explosions, appropriate safety measures must be taken to minimize the risk. Adherence to the safety measures and the flawless condition of the so-called EX systems are regularly checked by specialist staff.

EX systems exist in many sectors. This of course includes companies that work with flammable substances. Gas stations or systems with tanks in which flammable or potentially explosive substances are stored serve as examples. But other sectors are also affected. The chemical industry works with a large number of substances that are inherently explosive or if they react with another substance. Serious dust explosions can occur in mills, but also in wood processing plants. Mining is also particularly at risk due to the gases released.

Electrical installations in hazardous areas

Electrical systems should only be used with the greatest caution in areas where there is a risk of explosion. They pose a particularly great hazard in a so-called area subject to explosion hazards, since sparks can occur as a result of electrical discharge, which ultimately sets the explosive reaction in motion. However, if an electrical system is required in an area subject to explosion hazards, it must meet the highest safety requirements. This starts with avoiding flammable sparks, choosing the right equipment, cables and lines, and making the fundamental decision about which system is suitable for the hazardous area.

What are potentially explosive areas?

Potentially explosive areas are those places in the facility where, under certain conditions, explosions can occur. Potentially explosive areas are divided into three zones for grading:

• Zone 0 or 20: There is (almost) always an explosive atmosphere. As a guideline, more than 50% of the regular operating time can be assumed hazardous.
• Zone 1 or 21: There is an occasional risk of explosion during normal operation, for example during decanting or sampling.
• Zone 2 or 22: With this classification, it is assumed that the explosion hazard arises only rarely or for a short period of time. This should not be the case in normal operation, but in the event of failures or malfunctions.
• Zones 0, 1 and 2 are assigned if the risk of explosion is caused by combustible or flammable gases, vapours and mists.
• Zone 20, 21 or 22 relates to potentially explosive areas due to combustible dusts.

Explosion protection measures

An explosion occurs when three components meet: an oxidizable substance, an oxidizer and an ignition source. Protective measures are classified according to which component they make harmless.

• Primary explosion protection: Measures to prevent or reduce the formation of a potentially explosive atmosphere.
• Secondary explosion protection: Measures to prevent the ignition of a potentially explosive atmosphere.
• Tertiary explosion protection: Measures that reduce the effects of an explosion to a harmless level.

Synonyms for ex-systems

• Explosive system
• Ex system